<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>计算器</title>
<style>
    [type=submit]{
        width:33px;
        heifht:15px;
        text-align: center;
        margin: 0px;
        padding: 0px;
    }
</style>


</head>
<body>

       <tbody class="tbody" align="center">
        <tr >
            <td><button type="submit">%</button></td>
            <td><button type="submit">√</button></td>
            <td><button type="submit">×²</button></td>
            <td><button type="submit">1/x</button></td>
        </tr>
        <br/>
        <tr>
            <td><button type="submit">CE</button></td>
            <td><button type="submit">C</button></td>
            <td><button type="submit"><=</button></td>
            <td><button type="submit">➗</button></td>
        </tr>
        <br/>
        <tr>
            <td><button type="submit">7</button></td>
            <td><button type="submit">8</button></td>
            <td><button type="submit">9</button></td>
            <td><button type="submit">X</button></td>
        </tr> <tr>
            <td><button type="submit">4</button></td>
            <td><button type="submit">5</button></td>
            <td><button type="submit">6</button></td>
            <td><button type="submit">-</button></td>
        </tr> <tr>
            <td>1</td>
            <td>2</td>
            <td>3</td>
            <td>+</td>
        </tr> <tr>
            <td>±</td>
            <td>0</td>
            <td>.</td>
            <td>=</td>
        </tr>
       </tbody>

</body>
</html>